The present disclosure relates generally to an underground gas main stop-off system, and particularly to an in situ launch system for an underground gas main stop-off system.
Underground gas mains are typically part of a low pressure (¼ PSI, for example) distribution system, and on occasion require access by gas company personnel to the underground gas main pipe for emergency or maintenance situations. An existing method of stopping-off gas flow in a low pressure cast iron or steel gas main requires a field crew to make an excavation to expose the main pipe, tap the main pipe and install a stopper. This procedure is expensive, disruptive to the environment and general public, and very time consuming when considering that a quick shut down is of utmost importance during an emergency or maintenance situation.
While existing means for stopping-off gas flow in an emergency or maintenance situation may be suitable for their intended purpose, the art relating to stopping-off gas flow in a low pressure gas main would be advanced with a gas main stop-off system that does not require excavation to expose the gas main pipe.
This background information is provided to reveal information believed by the applicant to be of possible relevance to the present invention. No admission is necessarily intended, nor should be construed, that any of the preceding information constitutes prior art against the present invention.